/**
 * @file
 * TCP API (to be used from TCPIP thread)\n
 * See also @ref tcp_raw
 */

/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 */
#ifndef LWIP_HDR_TCP_H
#define LWIP_HDR_TCP_H

#include "lwip/opt.h"

#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */

#include "lwip/tcpbase.h"
#include "lwip/mem.h"
#include "lwip/pbuf.h"
#include "lwip/ip.h"
#include "lwip/icmp.h"
#include "lwip/err.h"
#include "lwip/ip6.h"
#include "lwip/ip6_addr.h"

#ifdef __cplusplus
extern "C"
{
#endif

    struct tcp_pcb;
    struct tcp_pcb_listen;

    /** Function prototype for tcp accept callback functions. Called when a new
     * connection can be accepted on a listening pcb.
     *
     * @param arg Additional argument to pass to the callback function (@see tcp_arg())
     * @param newpcb The new connection pcb
     * @param err An error code if there has been an error accepting.
     *            Only return ERR_ABRT if you have called tcp_abort from within the
     *            callback function!
     */
    typedef err_t (*tcp_accept_fn)(void* arg, struct tcp_pcb* newpcb, err_t err);

    /** Function prototype for tcp receive callback functions. Called when data has
     * been received.
     *
     * @param arg Additional argument to pass to the callback function (@see tcp_arg())
     * @param tpcb The connection pcb which received data
     * @param p The received data (or NULL when the connection has been closed!)
     * @param err An error code if there has been an error receiving
     *            Only return ERR_ABRT if you have called tcp_abort from within the
     *            callback function!
     */
    typedef err_t (*tcp_recv_fn)(void* arg, struct tcp_pcb* tpcb, struct pbuf* p, err_t err);

    /** Function prototype for tcp sent callback functions. Called when sent data has
     * been acknowledged by the remote side. Use it to free corresponding resources.
     * This also means that the pcb has now space available to send new data.
     *
     * @param arg Additional argument to pass to the callback function (@see tcp_arg())
     * @param tpcb The connection pcb for which data has been acknowledged
     * @param len The amount of bytes acknowledged
     * @return ERR_OK: try to send some data by calling tcp_output
     *            Only return ERR_ABRT if you have called tcp_abort from within the
     *            callback function!
     */
    typedef err_t (*tcp_sent_fn)(void* arg, struct tcp_pcb* tpcb, u16_t len);

    /** Function prototype for tcp poll callback functions. Called periodically as
     * specified by @see tcp_poll.
     *
     * @param arg Additional argument to pass to the callback function (@see tcp_arg())
     * @param tpcb tcp pcb
     * @return ERR_OK: try to send some data by calling tcp_output
     *            Only return ERR_ABRT if you have called tcp_abort from within the
     *            callback function!
     */
    typedef err_t (*tcp_poll_fn)(void* arg, struct tcp_pcb* tpcb);

    /** Function prototype for tcp error callback functions. Called when the pcb
     * receives a RST or is unexpectedly closed for any other reason.
     *
     * @note The corresponding pcb is already freed when this callback is called!
     *
     * @param arg Additional argument to pass to the callback function (@see tcp_arg())
     * @param err Error code to indicate why the pcb has been closed
     *            ERR_ABRT: aborted through tcp_abort or by a TCP timer
     *            ERR_RST: the connection was reset by the remote host
     */
    typedef void (*tcp_err_fn)(void* arg, err_t err);

    /** Function prototype for tcp connected callback functions. Called when a pcb
     * is connected to the remote side after initiating a connection attempt by
     * calling tcp_connect().
     *
     * @param arg Additional argument to pass to the callback function (@see tcp_arg())
     * @param tpcb The connection pcb which is connected
     * @param err An unused error code, always ERR_OK currently ;-) @todo!
     *            Only return ERR_ABRT if you have called tcp_abort from within the
     *            callback function!
     *
     * @note When a connection attempt fails, the error callback is currently called!
     */
    typedef err_t (*tcp_connected_fn)(void* arg, struct tcp_pcb* tpcb, err_t err);

#if LWIP_WND_SCALE
#define RCV_WND_SCALE(pcb, wnd) (((wnd) >> (pcb)->rcv_scale))
#define SND_WND_SCALE(pcb, wnd) (((wnd) << (pcb)->snd_scale))
#define TCPWND16(x)             ((u16_t)LWIP_MIN((x), 0xFFFF))
#define TCP_WND_MAX(pcb)        ((tcpwnd_size_t)(((pcb)->flags & TF_WND_SCALE) ? TCP_WND : TCPWND16(TCP_WND)))
#else
#define RCV_WND_SCALE(pcb, wnd) (wnd)
#define SND_WND_SCALE(pcb, wnd) (wnd)
#define TCPWND16(x)             (x)
#define TCP_WND_MAX(pcb)        TCP_WND
#endif
/* Increments a tcpwnd_size_t and holds at max value rather than rollover */
#define TCP_WND_INC(wnd, inc)                  \
    do                                         \
    {                                          \
        if ((tcpwnd_size_t)(wnd + inc) >= wnd) \
        {                                      \
            wnd = (tcpwnd_size_t)(wnd + inc);  \
        }                                      \
        else                                   \
        {                                      \
            wnd = (tcpwnd_size_t)-1;           \
        }                                      \
    } while (0)

#if LWIP_TCP_SACK_OUT
    /** SACK ranges to include in ACK packets.
     * SACK entry is invalid if left==right. */
    struct tcp_sack_range
    {
        /** Left edge of the SACK: the first acknowledged sequence number. */
        u32_t left;
        /** Right edge of the SACK: the last acknowledged sequence number +1 (so first NOT acknowledged). */
        u32_t right;
    };
#endif /* LWIP_TCP_SACK_OUT */

    /** Function prototype for deallocation of arguments. Called *just before* the
     * pcb is freed, so don't expect to be able to do anything with this pcb!
     *
     * @param id ext arg id (allocated via @ref tcp_ext_arg_alloc_id)
     * @param data pointer to the data (set via @ref tcp_ext_arg_set before)
     */
    typedef void (*tcp_extarg_callback_pcb_destroyed_fn)(u8_t id, void* data);

    /** Function prototype to transition arguments from a listening pcb to an accepted pcb
     *
     * @param id ext arg id (allocated via @ref tcp_ext_arg_alloc_id)
     * @param lpcb the listening pcb accepting a connection
     * @param cpcb the newly allocated connection pcb
     * @return ERR_OK if OK, any error if connection should be dropped
     */
    typedef err_t (*tcp_extarg_callback_passive_open_fn)(u8_t id, struct tcp_pcb_listen* lpcb, struct tcp_pcb* cpcb);

    /** A table of callback functions that is invoked for ext arguments */
    struct tcp_ext_arg_callbacks
    {
        /** @ref tcp_extarg_callback_pcb_destroyed_fn */
        tcp_extarg_callback_pcb_destroyed_fn destroy;
        /** @ref tcp_extarg_callback_passive_open_fn */
        tcp_extarg_callback_passive_open_fn passive_open;
    };

#define LWIP_TCP_PCB_NUM_EXT_ARG_ID_INVALID 0xFF

#if LWIP_TCP_PCB_NUM_EXT_ARGS
    /* This is the structure for ext args in tcp pcbs (used as array) */
    struct tcp_pcb_ext_args
    {
        const struct tcp_ext_arg_callbacks* callbacks;
        void* data;
    };
/* This is a helper define to prevent zero size arrays if disabled */
#define TCP_PCB_EXTARGS struct tcp_pcb_ext_args ext_args[LWIP_TCP_PCB_NUM_EXT_ARGS];
#else
#define TCP_PCB_EXTARGS
#endif

    typedef u16_t tcpflags_t;
#define TCP_ALLFLAGS 0xffffU

/**
 * members common to struct tcp_pcb and struct tcp_listen_pcb
 */
#define TCP_PCB_COMMON(type)              \
    type* next; /* for the linked list */ \
    void* callback_arg;                   \
    TCP_PCB_EXTARGS                       \
    enum tcp_state state; /* TCP state */ \
    u8_t prio;                            \
    /* ports are in host byte order */    \
    u16_t local_port

    /** the TCP protocol control block for listening pcbs */
    struct tcp_pcb_listen
    {
        /** Common members of all PCB types */
        IP_PCB;
        /** Protocol specific PCB members */
        TCP_PCB_COMMON(struct tcp_pcb_listen);

#if LWIP_CALLBACK_API
        /* Function to call when a listener has been connected. */
        tcp_accept_fn accept;
#endif /* LWIP_CALLBACK_API */

#if TCP_LISTEN_BACKLOG
        u8_t backlog;
        u8_t accepts_pending;
#endif /* TCP_LISTEN_BACKLOG */
    };

    /** the TCP protocol control block */
    struct tcp_pcb
    {
        /** common PCB members */
        IP_PCB;
        /** protocol specific PCB members */
        TCP_PCB_COMMON(struct tcp_pcb);

        /* ports are in host byte order */
        u16_t remote_port;

        tcpflags_t flags;
#define TF_ACK_DELAY   0x01U /* Delayed ACK. */
#define TF_ACK_NOW     0x02U /* Immediate ACK. */
#define TF_INFR        0x04U /* In fast recovery. */
#define TF_CLOSEPEND   0x08U /* If this is set, tcp_close failed to enqueue the FIN (retried in tcp_tmr) */
#define TF_RXCLOSED    0x10U /* rx closed by tcp_shutdown */
#define TF_FIN         0x20U /* Connection was closed locally (FIN segment enqueued). */
#define TF_NODELAY     0x40U /* Disable Nagle algorithm */
#define TF_NAGLEMEMERR 0x80U /* nagle enabled, memerr, try to output to prevent delayed ACK to happen */
#if LWIP_WND_SCALE
#define TF_WND_SCALE 0x0100U /* Window Scale option enabled */
#endif
#if TCP_LISTEN_BACKLOG
#define TF_BACKLOGPEND 0x0200U /* If this is set, a connection pcb has increased the backlog on its listener */
#endif
#if LWIP_TCP_TIMESTAMPS
#define TF_TIMESTAMP 0x0400U /* Timestamp option enabled */
#endif
#define TF_RTO 0x0800U /* RTO timer has fired, in-flight data moved to unsent and being retransmitted */
#if LWIP_TCP_SACK_OUT
#define TF_SACK 0x1000U /* Selective ACKs enabled */
#endif

        /* the rest of the fields are in host byte order
           as we have to do some math with them */

        /* Timers */
        u8_t polltmr, pollinterval;
        u8_t last_timer;
        u32_t tmr;

        /* receiver variables */
        u32_t rcv_nxt;             /* next seqno expected */
        tcpwnd_size_t rcv_wnd;     /* receiver window available */
        tcpwnd_size_t rcv_ann_wnd; /* receiver window to announce */
        u32_t rcv_ann_right_edge;  /* announced right edge of window */

#if LWIP_TCP_SACK_OUT
        /* SACK ranges to include in ACK packets (entry is invalid if left==right) */
        struct tcp_sack_range rcv_sacks[LWIP_TCP_MAX_SACK_NUM];
#define LWIP_TCP_SACK_VALID(pcb, idx) ((pcb)->rcv_sacks[idx].left != (pcb)->rcv_sacks[idx].right)
#endif /* LWIP_TCP_SACK_OUT */

        /* Retransmission timer. */
        s16_t rtime;

        u16_t mss; /* maximum segment size */

        /* RTT (round trip time) estimation variables */
        u32_t rttest; /* RTT estimate in 500ms ticks */
        u32_t rtseq;  /* sequence number being timed */
        s16_t sa, sv; /* @see "Congestion Avoidance and Control" by Van Jacobson and Karels */

        s16_t rto; /* retransmission time-out (in ticks of TCP_SLOW_INTERVAL) */
        u8_t nrtx; /* number of retransmissions */

        /* fast retransmit/recovery */
        u8_t dupacks;
        u32_t lastack; /* Highest acknowledged seqno. */

        /* congestion avoidance/control variables */
        tcpwnd_size_t cwnd;
        tcpwnd_size_t ssthresh;

        /* first byte following last rto byte */
        u32_t rto_end;

        /* sender variables */
        u32_t snd_nxt;             /* next new seqno to be sent */
        u32_t snd_wl1, snd_wl2;    /* Sequence and acknowledgement numbers of last
                                      window update. */
        u32_t snd_lbb;             /* Sequence number of next byte to be buffered. */
        tcpwnd_size_t snd_wnd;     /* sender window */
        tcpwnd_size_t snd_wnd_max; /* the maximum sender window announced by the remote host */

        tcpwnd_size_t snd_buf; /* Available buffer space for sending (in bytes). */
#define TCP_SNDQUEUELEN_OVERFLOW (0xffffU - 3)
        u16_t snd_queuelen; /* Number of pbufs currently in the send buffer. */

#if TCP_OVERSIZE
        /* Extra bytes available at the end of the last pbuf in unsent. */
        u16_t unsent_oversize;
#endif /* TCP_OVERSIZE */

        tcpwnd_size_t bytes_acked;

        /* These are ordered by sequence number: */
        struct tcp_seg* unsent;  /* Unsent (queued) segments. */
        struct tcp_seg* unacked; /* Sent but unacknowledged segments. */
#if TCP_QUEUE_OOSEQ
        struct tcp_seg* ooseq; /* Received out of sequence segments. */
#endif                         /* TCP_QUEUE_OOSEQ */

        struct pbuf* refused_data; /* Data previously received but not yet taken by upper layer */

#if LWIP_CALLBACK_API || TCP_LISTEN_BACKLOG
        struct tcp_pcb_listen* listener;
#endif /* LWIP_CALLBACK_API || TCP_LISTEN_BACKLOG */

#if LWIP_CALLBACK_API
        /* Function to be called when more send buffer space is available. */
        tcp_sent_fn sent;
        /* Function to be called when (in-sequence) data has arrived. */
        tcp_recv_fn recv;
        /* Function to be called when a connection has been set up. */
        tcp_connected_fn connected;
        /* Function which is called periodically. */
        tcp_poll_fn poll;
        /* Function to be called whenever a fatal error occurs. */
        tcp_err_fn errf;
#endif /* LWIP_CALLBACK_API */

#if LWIP_TCP_TIMESTAMPS
        u32_t ts_lastacksent;
        u32_t ts_recent;
#endif /* LWIP_TCP_TIMESTAMPS */

        /* idle time before KEEPALIVE is sent */
        u32_t keep_idle;
#if LWIP_TCP_KEEPALIVE
        u32_t keep_intvl;
        u32_t keep_cnt;
#endif /* LWIP_TCP_KEEPALIVE */

        /* Persist timer counter */
        u8_t persist_cnt;
        /* Persist timer back-off */
        u8_t persist_backoff;
        /* Number of persist probes */
        u8_t persist_probe;

        /* KEEPALIVE counter */
        u8_t keep_cnt_sent;

#if LWIP_WND_SCALE
        u8_t snd_scale;
        u8_t rcv_scale;
#endif
    };

#if LWIP_EVENT_API

    enum lwip_event
    {
        LWIP_EVENT_ACCEPT,
        LWIP_EVENT_SENT,
        LWIP_EVENT_RECV,
        LWIP_EVENT_CONNECTED,
        LWIP_EVENT_POLL,
        LWIP_EVENT_ERR
    };

    err_t lwip_tcp_event(void* arg, struct tcp_pcb* pcb, enum lwip_event, struct pbuf* p, u16_t size, err_t err);

#endif /* LWIP_EVENT_API */

    /* Application program's interface: */
    struct tcp_pcb* tcp_new(void);
    struct tcp_pcb* tcp_new_ip_type(u8_t type);

    void tcp_arg(struct tcp_pcb* pcb, void* arg);
#if LWIP_CALLBACK_API
    void tcp_recv(struct tcp_pcb* pcb, tcp_recv_fn recv);
    void tcp_sent(struct tcp_pcb* pcb, tcp_sent_fn sent);
    void tcp_err(struct tcp_pcb* pcb, tcp_err_fn err);
    void tcp_accept(struct tcp_pcb* pcb, tcp_accept_fn accept);
#endif /* LWIP_CALLBACK_API */
    void tcp_poll(struct tcp_pcb* pcb, tcp_poll_fn poll, u8_t interval);

#define tcp_set_flags(pcb, set_flags)                            \
    do                                                           \
    {                                                            \
        (pcb)->flags = (tcpflags_t)((pcb)->flags | (set_flags)); \
    } while (0)
#define tcp_clear_flags(pcb, clr_flags)                                                        \
    do                                                                                         \
    {                                                                                          \
        (pcb)->flags = (tcpflags_t)((pcb)->flags & (tcpflags_t)(~(clr_flags) & TCP_ALLFLAGS)); \
    } while (0)
#define tcp_is_flag_set(pcb, flag) (((pcb)->flags & (flag)) != 0)

#if LWIP_TCP_TIMESTAMPS
#define tcp_mss(pcb) (((pcb)->flags & TF_TIMESTAMP) ? ((pcb)->mss - 12) : (pcb)->mss)
#else /* LWIP_TCP_TIMESTAMPS */
/** @ingroup tcp_raw */
#define tcp_mss(pcb) ((pcb)->mss)
#endif /* LWIP_TCP_TIMESTAMPS */
/** @ingroup tcp_raw */
#define tcp_sndbuf(pcb) (TCPWND16((pcb)->snd_buf))
/** @ingroup tcp_raw */
#define tcp_sndqueuelen(pcb) ((pcb)->snd_queuelen)
/** @ingroup tcp_raw */
#define tcp_nagle_disable(pcb) tcp_set_flags(pcb, TF_NODELAY)
/** @ingroup tcp_raw */
#define tcp_nagle_enable(pcb) tcp_clear_flags(pcb, TF_NODELAY)
/** @ingroup tcp_raw */
#define tcp_nagle_disabled(pcb) tcp_is_flag_set(pcb, TF_NODELAY)

#if TCP_LISTEN_BACKLOG
#define tcp_backlog_set(pcb, new_backlog)                                                    \
    do                                                                                       \
    {                                                                                        \
        LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", (pcb)->state == LISTEN); \
        ((struct tcp_pcb_listen*)(pcb))->backlog = ((new_backlog) ? (new_backlog) : 1);      \
    } while (0)
    void tcp_backlog_delayed(struct tcp_pcb* pcb);
    void tcp_backlog_accepted(struct tcp_pcb* pcb);
#else /* TCP_LISTEN_BACKLOG */
#define tcp_backlog_set(pcb, new_backlog)
#define tcp_backlog_delayed(pcb)
#define tcp_backlog_accepted(pcb)
#endif /* TCP_LISTEN_BACKLOG */
#define tcp_accepted(pcb)     \
    do                        \
    {                         \
        LWIP_UNUSED_ARG(pcb); \
    } while (0) /* compatibility define, not needed any more */

    void tcp_recved(struct tcp_pcb* pcb, u16_t len);
    err_t tcp_bind(struct tcp_pcb* pcb, const ip_addr_t* ipaddr, u16_t port);
    void tcp_bind_netif(struct tcp_pcb* pcb, const struct netif* netif);
    err_t tcp_connect(struct tcp_pcb* pcb, const ip_addr_t* ipaddr, u16_t port, tcp_connected_fn connected);

    struct tcp_pcb* tcp_listen_with_backlog_and_err(struct tcp_pcb* pcb, u8_t backlog, err_t* err);
    struct tcp_pcb* tcp_listen_with_backlog(struct tcp_pcb* pcb, u8_t backlog);
/** @ingroup tcp_raw */
#define tcp_listen(pcb) tcp_listen_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG)

    void tcp_abort(struct tcp_pcb* pcb);
    err_t tcp_close(struct tcp_pcb* pcb);
    err_t tcp_shutdown(struct tcp_pcb* pcb, int shut_rx, int shut_tx);

    err_t tcp_write(struct tcp_pcb* pcb, const void* dataptr, u16_t len, u8_t apiflags);

    void tcp_setprio(struct tcp_pcb* pcb, u8_t prio);

    err_t tcp_output(struct tcp_pcb* pcb);

    err_t tcp_tcp_get_tcp_addrinfo(struct tcp_pcb* pcb, int local, ip_addr_t* addr, u16_t* port);

#define tcp_dbg_get_tcp_state(pcb) ((pcb)->state)

/* for compatibility with older implementation */
#define tcp_new_ip6() tcp_new_ip_type(IPADDR_TYPE_V6)

#if LWIP_TCP_PCB_NUM_EXT_ARGS
    u8_t tcp_ext_arg_alloc_id(void);
    void tcp_ext_arg_set_callbacks(
        struct tcp_pcb* pcb,
        uint8_t id,
        const struct tcp_ext_arg_callbacks* const callbacks);
    void tcp_ext_arg_set(struct tcp_pcb* pcb, uint8_t id, void* arg);
    void* tcp_ext_arg_get(const struct tcp_pcb* pcb, uint8_t id);
#endif

#ifdef __cplusplus
}
#endif

#endif /* LWIP_TCP */

#endif /* LWIP_HDR_TCP_H */
